I don't know of a book that solely focuses on small stakes No Limit Hold'em. But, Miller, Sklansky, and Malmuth's Small Stakes Hold'em book is the single best book on small stakes Limit Hold'em. That being said, if you read MIller, Sklansky, & malmuth and just play a little tighter than they suggest for Limit, you should be fine. I follow their strategies when playing Limit Hold'em and when playing No Limit Hold'em tournaments. I just mix in a little betting strategy from Dan Harrington's No Limit books and it works fine for me.